Thomas henry marten



T. H. MARTEN. SH'IP'S LIFE son DAVIT.

Patentad Oct. 21,1919.

APPLICATION FILED MAR. 5. 1918.

2 SHEETSSHEET I.

INVENTOR:

THE COLUMBIA PLANOGRAPH 10., WASHINGTON. D. c.

I. H. MARTEN.

SHIPS LIFE BOAT DAVIT.

APPLICATION man MAR. 5. 191a Patented Oct. 21, 1919.

2 SHEETS-SHEET 2.

UNITED STATES THOMAS HENRY MARTEN, or TORONTO, ONTARIO, oAnADA. W

SHIPS LIFE-BOAT DAVIT.

Specification of Letters Patent. Patented Oct. 21, 1919.

Application filed March 5, 1918. Serial No, 220,514.

swings about a fixed pivot in a' vertical'plane' athwart-ship which is particularly adapted to resist torsional stresses set up in the boom by the suspension of the load from a. point offset laterally from the center line of the boom at its upper end.

A further and important object is to pro-v vide a frame and mechamsm for operatingthe boom which impart fore and aft stability to the boom, and further to render the construction of simple and extremely strong nature which may be manufactured at reasonable cost.

The principal feature of the invention consists in the novel construction and arrangement of parts, whereby the athwartship angular profile of the boom is formed to effectively resist torsional stresses and to enable the frame structure being maintained entirely within the line of the ships side and whereby the boom is pivoted at its foot and substantially supported by the frame against torsional and fore and aft stresses.

A further important featureconsists in the novel manner of connection between the boom and the operating screw:

In the accompanying drawings, Figure 1* is a side elevational view ofmy improved davit showing the boom in its extreme in board position in full lines, the position of the lower part of the boom and operating members being shown in dotted lines in the extreme outboard position.

Fig. 2 is an elevational view of the davit taken from the in'board side.

Like numerals of reference indicate corresponding parts in each figure.

The frame 1 of the davit is preferably constructed of a rigid steel casting having the pivot bearings 2 at the base and close to the outboard side, said bearings form ing the pivot support for the boom 3,

PATENT OFFICE.

The boom is formed with its lower end v bifurcated to straddle the frame, the ends beingsupported on the pivot pin 4 carried in the bearings 2 and lockedagainst spreading by the cross bolt 5.

The profile of the boom is of obtuse angular formation and the lower portion 6 rests in an inwardly inclined direction extending from the pivot bearings 2 toward the in: board end of the upper part of the frame while the upper portion. of theboo-m is in an approximately upright position. and

is provided with an offset curved upper,

end 22 extendingin a-foreandaft direction to permit ,the: proper hanging of the 1 tackle blocks ina suitable mannerto engage the life boat. 1 j

A bar 8 preferably of circular cross section is secured in the upper ends of the outboard upright 9 and inboard post 10 of the frame and is arrangedsubstantially parallel to the chord of the arcof travel of the point of connection between the boom and its operating members, that is, in an upward and outward incline.v A threaded spindle 12 is journaled in suitable bearings inthe upright 9 and post 10 immediately below and parallel with the bar 8 and a suitable brace piece 11 is arranged below said spindle and forms part of the-rigid frame. a v 7 A crosshead 13 slidab-ly embraces the bar 8 and is provided with a pair of downwardly extending lugs14 which loosely en'- circle the spindle v12 having a space .15- ar-. ranged between them in which is located a traveling nut 16 threaded on the spindle.

A bearing 17 is transversely arranged upon the upper side of the crosshead 13 and alink 18 islpivotally supported by the pivot pin 19 carried in the bearing 17, said link being of bifurcated structure embracing the outer ends of the bearing. The outer end of the link extends between the sides of the bifurcated end of the boom and is pivotally connected thereto by the pivot pin 20.

It will be seen that upon the rotation of the spindle by means of the crank 21 the crosshead 13 is'caused to slide upon the bar 8 and the outward movement thereof is transmitted to the boom through the link 18.

The boom swings upon the pivot pin 4,

consequently the pivot pin 20 swings in an are about the center of the pivot pin& and the outer end of the link swings upwardly and downwardly as the boom travels outwardly to accommodate the change of position of the pivot pin 20 in relation to the crosshead and the operating screw. As the first movement of the boom head is in an ascending are due to the normal position of the boom being inboard of its center of gravity all slack and stretch in the tackle ropes is taken up and the life boat is lifted well clear of the chocks. The mechanical action is. therefore very positive and the parts are of strong and simple construction.

The bifurcated formation of the boom gives to it substantial fore and aft stability and the angular formation of its profile resists the torsional stresses set up by the offset position of the load at its upper end. The pivot pin 20 with the substantial vstructure of the operating link and crosshead add materially to the strength of the boom in receivin the torsional and fore and aft stresses anc a very strong structure is pro-v duced.

' It will be noted that the peculiar obtuse angular formation of the profile of thebooin provides that the lower portion doesnot extend beyond the frame whenthe boom head is in its outermost position and the maximum support is therefore maintained, consequently the link connection between the boom and operating crosshead is short and renders the whole structure rigid and stable;

It will be noted particularly that. all

bearings, that is, the bearing of the main pivot of the boom, the bearing of the crosshead upon the bar 8 and the bearing connections of the link are all extremely long and themaximum stability is therefore obtained.

As previously described the angle of inclination of the operating screw is arranged parallel with the chord "of the arc of travel of theboom-link pivot, consequently when the boom is in the extreme inboard and out? board positions the link assumes a position parallel to the screw and crosshead bar imparting the utmost rigidity to the structure.

The boat is supported upon suitable tackle ropes suspended from the boom head 22,

and. the working. part of the rope is carried around the gipsy head 23 and belayed to the cleat 24. j r

A davit such as described will be ex Copies of this patent may be obtained for tremely eflicient and any failure on the part of the screw will not allow the clavit to escape as it is distinctly secured to the link and crosshead and held within the limits of the frame.

What I claim as my invention is 1. A ships life boat davit, comprising in combination a rigid frame, a boom pivotally secured at its lower end to said frame at the outboard end thereof and extending in an inboard and upwardly inclined direction to the inner and upper portion of the frame and having an upright portion adapted to support the boat, means operating in said frame for swinging the boom on its pivot, said means being operatively connected to the boom at the upper end of the incline portion and being adapted to support the boom laterally.

2. A ships life boat davit, comprising in combination, a rigid frame, a boom formed with a bifurcated lower end straddling said frame and having its foot piv' oted to the frame at its outboard end and extending angularly inwardly and upwardly and formed with its upper end extending in obtuse angular relationship to the bifurcated lower end, a cross head slidably arranged in said frame to travel in a path substantially on the chord of the arc of the swing of the boom about its pivot, means for traveling said crosshead, and alink connection secured to said crosshead and pivotally connected to the boom.

3, A ships life boat davit, comprising, a rigid frame, a boom formed with a bifurcated lower end straddling said frame and having its foot pivoted at the outboard side of said frame, a crosshead guide sloping upwardly and outwardly and extend-' five cents each, by addressing the Commissioner of Patents.

Washington, D. C. 

